Image:
Geothermal Power Plant

Geothermal energy plant near Reykjavik, north west Iceland. Volcanic rocks are visible behind the plant.

Beneath our feet, in the Earth's interior, lies rocks containing vast amounts of heat. This heat is a constant source of energy and can be used to produce geothermal (meaning 'earth heat') electricity. About 25 countries use this type of electricit, but only a few use it for more than 15 per cent of their electric needs. It can be difficult to extract this energy, especially if the rocks are too far below the surface.